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TROPICAL DEPRESSION THREE DISCUSSION NUMBER 2
NATIONAL WEATHER SERVICE MIAMI FL
11 PM EDT WED AUG 18 1999
AIRCRAFT RECONNAISSANCE AND SATELLITE DATA THIS EVENING INDICATE
THAT THE TROPICAL DEPRESSION REMAINS VERY POORLY ORGANIZED...WITHOUT
A WELL-DEFINED LOW-LEVEL CENTER. THERE IS LITTLE CONVECTION NEAR
THE LOCATION WHERE THE AIR FORCE RESERVE AIRCRAFT REPORTED A
CENTER...AND SATELLITE IMAGERY SUGGESTS THAT A MID LEVEL CENTER MAY
BE REDEVELOPING TO THE NORTHEAST.
INITIAL MOTION IS HIGHLY UNCERTAIN...BUT IS ESTIMATED TO BE 280/2.
THE NCEP GLOBAL MODEL SHOWS A RETROGRESSION OF THE MID-
TROPOSPHERIC RIDGE OVER THE SOUTH-CENTRAL UNITED STATES...WITH A
WEAKNESS EXTENDING NORTHEASTWARD FROM THE SOUTHWEST GULF TO A
DEVELOPING TROUGH OVER THE EASTERN UNITED STATES. THE GFDL AND AVN
SUGGEST THAT THE CYCLONE MAY REMAIN OVER THE SOUTHWEST GULF FOR THE
NEXT FEW DAYS. THE OFFICIAL FORECAST TRACK CALLS FOR A SLOW WEST-
NORTWESTWARD MOTION...BUT IF THE SYSTEM REFORMS TO THE NORTHEAST A
MORE NORTHERLY TRACK IS LIKELY.
THE DEPRESSION IS CURRENTLY EXPERIENCING SOME WEST-SOUTHWESTERLY
SHEAR DUE TO AN UPPER-LEVEL TROUGH OVER THE EXTREME WESTERN GULF.
THE GLOBAL MODEL FORECAST SHOWS THE TROUGH MOVING OFF TO THE WEST
AWAY FROM THE DEPRESSION WHICH MAY CREATE A MORE FAVORABLE
ENVIRONMENT BEYOND 24 HOURS.
FRANKLIN
FORECAST POSITIONS AND MAX WINDS
INITIAL 19/0300Z 19.6N 94.3W 30 KTS
12HR VT 19/1200Z 19.7N 94.7W 30 KTS
24HR VT 20/0000Z 19.9N 95.1W 30 KTS
36HR VT 20/1200Z 20.2N 95.5W 35 KTS
48HR VT 21/0000Z 20.5N 96.0W 40 KTS
72HR VT 22/0000Z 21.0N 97.0W 50 KTS
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